Psychosocial stress enhances time-based prospective memory in healthy young men

Forgetting of intentions (such as to take one's medication) is the most frequent everyday memory failure. No study so far has looked into the possible consequences stress might exert on memory for intentions (i.e., prospective memory). Twenty healthy young male adults were exposed to a psychosocial stress test and a non-stress condition. After a delay of 15 min, a time- and an event-based prospective memory task were administered during the peak of cortisol concentrations. Results show that participants performed significantly better in the time-based memory task after stress in comparison to the non-stress condition. In contrast, there was no stress effect on event-based prospective memory. The results demonstrate that prospective memory might be enhanced when participants are exposed to stress prior to the memory task and that this effect is associated to stress-related glucocorticoid effects.     

Immediate recall influences the effects of pre-encoding stress on emotional episodic long-term memory consolidation in healthy young men

The stress-associated activation of the hypothalamus-pituitary-adrenal axis influences memory. Several studies have supported the notion that post-learning stress enhances memory consolidation, while pre-retrieval stress impairs retrieval. Findings regarding the effects of pre-encoding stress, in contrast, have been rather inconsistent. In the current two studies, the impact of an immediate retrieval task on these effects was explored. In the first study, 24 healthy young male participants were exposed to a psychosocial laboratory stressor (Trier Social Stress Test) or a control condition before viewing positive, negative, and neutral photographs, which were accompanied by a brief narrative. Immediate as well as delayed (24?h later) free recall was assessed. Stress was expected to enhance emotional long-term memory without affecting immediate recall performance. Stress caused a significant increase in salivary cortisol concentrations but had no significant effects on immediate or delayed retrieval performance, even though a trend toward poorer memory of the stress group was apparent. Based on these findings, the second experiment tested the hypothesis that the beneficial effects of stress on emotional long-term memory performance might be abolished by an immediate recall test. In the second study (n?=?32), the same design was used, except for the omission of the immediate retrieval test. This time stressed participants recalled significantly more negative photographs compared to the control group. The present study indicates that an immediate retrieval attempt of material studied after stress exposure can prevent or even reverse the beneficial effects of pre-encoding stress on emotional long-term memory consolidation.     

Enhancing effects of acute psychosocial stress on priming of non-declarative memory in healthy young adults

Social stress affects cognitive processes in general, and memory performance in particular. However, the direction of these effects has not been clearly established, as it depends on several factors. Our aim was to determine the impact of the hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) reactivity to psychosocial stress on short-term non-declarative memory and declarative memory performance. Fifty-two young participants (18 men, 34 women) were subjected to the Trier Social Stress Task (TSST) and a control condition in a crossover design. Implicit memory was assessed by a priming test, and explicit memory was assessed by the Rey Auditory Verbal Learning Test (RAVLT). The TSST provoked greater salivary cortisol and salivary alpha-amylase (sAA) responses than the control task. Men had a higher cortisol response to stress than women, but no sex differences were found for sAA release. Stress was associated with an enhancement of priming but did not affect declarative memory. Additionally, the enhancement on the priming test was higher in those whose sAA levels increased more in response to stress (r(48)?=?0.339, p?=?0.018). Our results confirm an effect of acute stress on priming, and that this effect is related to SNS activity. In addition, they suggest a different relationship between stress biomarkers and the different memory systems.     

Semantic satiation in healthy young and older adults

In four experiments, semantic satiation was investigated in young and old adults. In the first two experiments, subjects were repeatedly presented a word (e.g.,dog) and then were presented a pair of words (e.g.,dog-cat ordog-chair) for a relatedness decision. The results of both experiments indicated that for the young adults, the relatedness effect (the difference between response latency on related and unrelated trials) decreased as a function of the number of times the satiated word was repeated, whereas for the older adults, there was no evidence of a decrease in the relatedness effect across repetitions of the satiated word. In the third experiment, we investigated whether phonological codes are also susceptible to satiation. This experiment was similar to the first two experiments with the exception that subjects made rhyme decisions (same-claim vs.same-dime) instead of semantic relatedness decisions. The results of this experiment did not yield any evidence of satiation for either the young adults or the older adults. The final experiment eliminated a simple decrease in attentional alertness or fatigue account of the semantic satiation effects found in the first two experiments. In this experiment, the repeated word was always unrelated to the pair of words presented for the relatedness decision. The results of this experiment did not yield any evidence of semantic satiation for either the young or the older adults. The discussion focuses on the mechanisms underlying semantic satiation and the implications of age-related changes in these mechanisms.     

Sleep facilitates consolidation of positive emotional memory in healthy older adults

ABSTRACT

Evidence has demonstrated that sleep-related memory consolidation declines in ageing. However, little is known about age-related changes to sleep-related emotional memory consolidation, especially when considering the positivity effect observed in older adults. In the present study, we sought to explore whether there is a positive emotional bias in sleep-related memory consolidation among healthy older adults. Young and older adults were randomly assigned either into a sleep or wake condition. All participants encoded positive, negative, and neutral stimuli and underwent recognition tests immediately (test 1), after a 12-hour sleep/wake interval (test 2), and 3 days after test 2 (test 3). Results showed that age-related differences of sleep beneficial effect were modulated by emotion valence. In particular, sleep selectively enhanced positive memory in older adults, while in young adults sleep beneficial effect was manifested in neutral memory. Moreover, the sleep beneficial effect can be maintained at least 3 days in both young and older adults. These findings suggest that older adults had preserved but positive bias of sleep-related memory consolidation, which could be one of the underlying mechanisms for their generally better emotional well-being in daily life. These findings highlight the dynamic interplay among sleep and emotional memory in older adults.     

Self-referencing enhances recollection in both young and older adults

Processing information in relation to the self enhances subsequent item recognition in both young and older adults and further enhances recollection at least in the young. Because older adults experience recollection memory deficits, it is unknown whether self-referencing improves recollection in older adults. We examined recollection benefits from self-referential encoding in older and younger adults and further examined the quality and quantity of episodic details facilitated by self-referencing. We further investigated the influence of valence on recollection, given prior findings of age group differences in emotional memory (i.e., “positivity effects”). Across the two experiments, young and older adults processed positive and negative adjectives either for self-relevance or for semantic meaning. We found that self-referencing, relative to semantic encoding, increased recollection memory in both age groups. In Experiment 1, both groups remembered proportionally more negative than positive items when adjectives were processed semantically; however, when adjectives were processed self-referentially, both groups exhibited evidence of better recollection for the positive items, inconsistent with a positivity effect in aging. In Experiment 2, both groups reported more episodic details associated with recollected items, as measured by a memory characteristic questionnaire, for the self-reference relative to the semantic condition. Overall, these data suggest that self-referencing leads to detail-rich memory representations reflected in higher rates of recollection across age.     

Self-reference enhances relational memory in young and older adults

The present study investigated the influence of self-reference on two kinds of relational memory, internal source memory and associative memory, in young and older adults. Participants encoded object–location word pairs using the strategies of imagination and sentence generation, either with reference to themselves or to a famous other (i.e., George Clooney or Oprah Winfrey). Both young and older adults showed memory benefits in the self-reference conditions compared to other-reference conditions on both tests, and the self-referential effects in older adults were not limited by low memory or executive functioning. These results suggest that self-reference can benefit relational memory in older adults relatively independently of basic memory and executive functions.     

Emotional influences on sit-to-walk in healthy young adults

The purpose of this study was to investigate influences of emotional feelings on sit-to-walk (STW). Eighteen healthy young adults performed STW while feeling sadness, anger, joy and neutral emotion. Emotions were elicited using an autobiographical memories task. We used an optoelectronic motion capture system to collect motion data and assessed kinematics of STW. Emotion-related differences in STW kinematics were consistent with differences in movement speed. Compared to neutral emotion, sadness was associated with increased STW duration and phase durations, decreased peak forward and vertical center-of-mass (COM) velocity, increased drop in forward COM velocity, and increased forward and vertical normalized jerk score (NJS). Anger and joy were associated with decreased STW duration and phase durations, increased peak forward and vertical COM velocity, decreased drop in forward COM velocity, and decreased forward and vertical NJS compared to neutral emotion. Findings suggest that emotional feelings affect movement speed, hesitation, and movement smoothness during STW.     

Trait impulsiveness and executive function in healthy young adults

Performance-based neuropsychological tests are often used to assess planning and impulse control, but the extent to which these measures reflect trait impulsiveness or specific dimensions of trait impulsiveness is not clear. This study used the Barratt Impulsiveness Scale-11 (BIS-11; [Patton, J. H., Stanford, M. S., & Barratt, E. S. (1995). Factor structure of the Barratt Impulsiveness Scale. Journal of Clinical Psychology, 51, 768–774.]) to examine the relationship between various dimensions of trait impulsiveness and performance on several executive function tests in healthy young adults. Total BIS-11 scores correlated with performance on measures of planning and impulse control. Higher non-planning impulsiveness scores, which indicate poorer self-control and lower cognitive complexity, correlated most strongly with performance on a maze test that measures planning and impulse control (r = .58). These results provide support for the convergent validity of pencil-and-paper maze-based measures of planning and impulse control.     

Acute stress persistently enhances estrogen levels in the female rat

Here we tested whether exposure to either tailshock or swim stress alters ovarian hormone levels, estrogen and progesterone, in females and whether the effects are persistent. Adrenal hormone levels were also measured in males and females. Estradiol levels were elevated in unstressed females during proestrus relative to females in other stages of estrous, and exposure to the stressors enhanced estradiol beyond basal levels. For females stressed during diestrus 2, estradiol levels were elevated immediately after stressor cessation and up to 24 hrs. Exposure to tailshock, but not swim-stress, transiently enhanced progesterone in females stressed during the stage of proestrus and estrus. Glucocorticoid levels were elevated in response to both stressors and were supraelevated in females under both basal and stress conditions relative to males, particularly in blood from females exposed to acute swim stress. These results indicate that exposure to a relatively acute stressful event immediately and persistently enhances serum estradiol and are discussed in the context of reports that exposure to the same stressors immediately and persistently impairs associative learning in the female rat.     

Prospective memory training in young adults enhances trained-task but not transfer-task performance

ABSTRACT

Training and transfer effects of prospective memory training have not been assessed in healthy young adults yet. The present study examined the effects of an 8-day prospective memory training programme using the Virtual Week computer game in 18–24-year-old students. Using the performance of an active control group as comparison, the study revealed a significant short-lived beneficial training-induced effect on a nearest-transfer task consisting of a different version of the trained task. No evidence was obtained for transfer effects to other tasks measuring prospective memory (near transfer), or to tasks measuring various executive functions or general intelligence (far transfer). These results were compared to those from a previous study in which an identical training and testing protocol was used in 13–15-year-old adolescents. This study did reveal some evidence of near and far transfer. The results of the two studies combined suggest a greater potential for prospective memory training to induce beneficial transfer effects in young adolescents than in young adults.     

Preadolescent religious experience enhances temporal lobe signs in normal young adults.

The hypothesis was verified that an ontogenetically earlier onset of temporal lobe transients, as defined by a preadolescent religious experience, facilitates more frequent and varied temporal lobe signs in adults. Data were collected for 868 male and female university students in psychology over a 10-year period; the 19% of students who reported this early experience displayed more frequent depersonalization, beliefs in psi phenomena, sensations of presence, sensitivity to odors, widened affect, childhood imaginary playmates, and left (writing) handedness. Early experiments were more likely to display confusion of boundaries between themselves, other people, and cosmic forces.     

Mediator-based encoding strategies in source monitoring in young and older adults

Past research has examined the contribution of mediator-based encoding strategies (interactive imagery and sentence generation) to individual (particularly age-related) differences in associative memory exclusively in the paired-associates paradigm. In the present study, we examined young and older adults' mediator-based strategy use on source-monitoring tasks. Participants spontaneously used mediator-based strategies to encode about 30% to 40% of word-source pairs and were able to follow instructions to use the specific mediator-based strategy of interactive imagery; mediator-based strategy use was associated with higher source memory and explained variance in source memory. There were no age-related differences in the patterns of mediator-based strategy production and utilization. Age-related differences in source memory were explained by age-related declines in the ability to bind information in memory (incidental memory for digit-symbol associations) but not by encoding strategy production. Results underscore the importance of assessing encoding strategy use for understanding individual differences in source memory. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Personality and attitudinal correlates of healthy and unhealthy lifestyles in young adults

Abstract

The relationship between healthy lifestyle and personality and attitudinal variables was analyzed with data collected from 809 men and 996 women aged 18–30 years in England, Belgium, Finland and Norway as part of the European Health and Behaviour Survey. A health practices index was constructed on the basis of performance of sixteen behaviours including smoking, alcohol consumption, exercise, sleep time and a variety of dietary and preventive practices. Scores on the health practices index were higher in women than men, but in both sexes the index was normally distributed. Consistently healthy practices were positively correlated with extraversion and optimism, and negatively associated with neuroticism, psychoticism and chance locus of control beliefs. These effects were maintained after controlling for social desirability, but together accounted for only a modest proportion of the variance in the health practices index. The results are discussed in relation to the factors characterising health conscious and unhealthy lifestyles.     

急性应激损伤错误监控与错误后调整

生活中,个体会时时关注自己的行为结果并及时做出调整以适应环境的变化。但在应激下个体能否有效地监控行为并做出适应性调整依然未知。本研究招募了52名男性大学生被试,将其随机分入应激组与控制组,采用特里尔社会应激测试(Trier Social Stress Test, TSST)诱发个体的应激反应,并结合错误意识任务(Error Awareness Task,EAT)探索个体急性应激下的错误监控与错误后调整过程。应激指标的结果显示应激组个体在应激任务后唾液皮质醇、心率、应激感知自我报告和负性情绪均显著高于控制组,表明急性应激的诱发是成功的。行为结果显示应激组的错误意识正确率显著低于控制组,错误意识反应时显著短于控制组;进一步地,应激组个体在意识到错误之后的试次上正确率显著低于未意识到错误之后的试次,并且应激组个体在意识到错误之后的试次上正确率低于控制组。结果表明急性应激降低了个体对错误反应的监控水平,即便在辨别出错误反应的情况下,个体的行为监控与调节也更差。本研究说明急性应激会损伤行为监控系统,导致个体的行为适应性下降。     

Direct and indirect measures of frequency monitoring in young and elderly adults

Memory for frequency of occurrence of novel material (Turkish words) was investigated in young and elderly adults via direct (absolute and relative frequency judgments) and indirect (reading speed) measures. Both young and elderly adults showed increased reading speed as a function of frequency of occurrence (Experiment 1). However, when asked explicitly to identify how often a word occurred (Experiment 1) or which word occurred more often (Experiment 2), elderly subjects were less accurate than young adults. These results support and extend research on age-related dissociations in memory.     

Acute stress rapidly and persistently enhances memory formation in the male rat

Previous studies, as well as the present one, report that acute exposure to intermittent tailshocks enhances classical eyeblink conditioning in male rats when trained 24 h after stressor cessation. In Experiment 1, it was determined that the facilitating effect of stress on conditioning could also be obtained in response to a stressor of acute inescapable swim stress but not inescapable noise or the unconditioned stimulus of periorbital eyelid stimulation. These selective responses arose despite comparable enhancements of the stress-related hormone corticosterone in response to tailshocks, periorbital eyelid stimulation, noise stress, and supraelevation in response to swim stress. Although corticosterone is necessary for the enhanced learning in response to stress (Beylin & Shors, 1999), these results suggest that it is not sufficient. In addition, the results suggest that the enhancement is not dependent on common characteristics between the stressor and the conditioning stimuli (stimulus generalization). In Experiment 2, it was determined that the facilitating effect of the stressor on conditioning occurs within 30 min of stressor cessation. Thus, the mechanism responsible for facilitating memory formation is rapidly induced as well as persistently expressed. In Experiment 3, it was determined that exposure to the stressor does not enhance performance of the conditioned response after the response has been acquired. Thus, exposure to the stressor enhances the formation of new associations rather than affecting retention or performance of the motor response. These studies extend the circumstances under which stress is known to enhance associative learning and implicate neural mechanisms of memory enhancement that are rapidly induced and persistently expressed.     

Perceptions of an over-ground induced temporal gait asymmetry by healthy young adults

Nearly 60% of individuals with stroke walk with temporal gait asymmetry (TGA; a phase inequality between the legs during gait). About half of individuals with TGA are unable to correctly identify the presence or direction of their asymmetry. If patients are unable to perceive their gait errors, it will be harder to correct them to improve their gait pattern. Perception of gait pattern error may be affected by the stroke itself; therefore, the objectives of this study were to determine how the gait of neurotypical individuals changes with an induced temporal asymmetry, and how perception of that TGA compares to actual asymmetry both before and after 15-min of exposure to the induced asymmetry. After baseline symmetry (measured as symmetry index (SI)) was assessed with a pressure sensitive mat, participants (n = 29) walked for 15 min over-ground with cuff weights (7.5% of body weight) on their non-dominant leg to induce TGA. Presence, direction, and magnitude of TGA was measured at five time points: 1) baseline, 2) immediately after unilateral loading (early adaptation (EA)), 3) at the end of 15 min of walking (late adaptation (LA)), 4) immediately after load removal (early deadaptation (EDA)), and 5) after the participant indicated that their gait had returned to baseline symmetry (late deadaptation (LDA). Presence, direction, and magnitude of perceived TGA was measured by self-report. Measured and perceived TGA changes over time were assessed with separate one-way repeated measures analyses of variance. Agreement between measured and perceived TGA was assessed. During EA, all participants walked asymmetrically, spending more time on the non-loaded limb compared to baseline (−12.67 [95%CI −14.56, −10.78], p < 0.0001). All but one participant perceived this TGA, however only fifteen (52%) correctly perceived both TGA presence and direction. At LA, the group remained asymmetric (−9.22 [95%CI −11.32, −7.12], p < 0.0001), but only 9 participants (31%) correctly perceived both the presence and direction of their TGA. Visual inspection of the data at each time point revealed most participants perceived TGA magnitude as greater than actual TGA. Overall, we find that TGA can be induced and maintained in neurotypical young adults. Perception of TGA direction is inaccurate and perception of TGA magnitude is grossly overestimated. Perceptions of TGA do not improve after a period of exposure to the new walking pattern. These preliminary findings indicate that accurately perceiving an altered gait pattern is a difficult task even for healthy young adults.     

Self-Reference enhances memory for multi-element events judged likely to happen in young and older adults

ABSTRACT

We investigated whether the strategy of self-reference can benefit memory for multi-element events, a kind of relational memory that is relatively less studied but highly relevant to daily life. Young and older adults imagined different person-object-location events with reference to themselves and two famous others (i.e., George Clooney and Oprah Winfrey), rated the likelihood that each event would happen, and then completed incidental memory tests on different pairs of elements within the event. We found that self-reference enhanced memory for object-location and person-object pairs in both age groups. Such self-reference effects were observed consistently only for events rated as likely to happen. There was also an overall memory advantage for the higher-likelihood events, which did not differ between young and older adults. Further, the self-reference effects were not correlated with memory functioning in either age group. Retrieval of within-event associations showed a significant level of dependency, which did not differ as a function of reference condition or likelihood category. These findings highlight the ways in which self-reference and prior knowledge improve relational memory, and suggest that the advantage of self-reference is not attributable to increased dependence of elements within complex events.     

Childhood abuse and vulnerability to depression: Cognitive scars in otherwise healthy young adults

Models of depression vulnerability posit that negative early experiences, such as exposure to childhood abuse (CA), increase vulnerability to depression later in life. Though most victims of CA do not go on to develop depression, the question remains as to whether these individuals retain cognitive ‘scars’ that may contribute to depression vulnerability. The present study examined the relationship between self-reported, retrospective CA and cognitive vulnerability to depression in a carefully selected sample of young adults without current or past psychopathology. We measured cognitive vulnerability with both a self-report questionnaire, the Dysfunctional Attitudes Scale (DAS), and a measure of information processing bias, the Scrambled Sentences Test (SST). Self-reported severity of CA was associated with increased cognitive vulnerability to depression on both the DAS and SST. Vulnerability to depression as measured by the SST, but not by the DAS, prospectively predicted increases in depressive symptoms over a 6-month period. Scores on the SST also interacted with CA to predict increases in depressive symptoms. These findings demonstrate the pernicious effects of CA even in those without current or past psychopathology.